Tire manufacturers often perform wear testing on tires. Tire tread wear may be influenced by a number of variables other than the tire construction and tread compound, such as: environmental factors (such as temperature and rain fall), driver severity (such as driving style and route composition), pavement characteristics, and tire and vehicle dynamic properties (such as weight, location of center of gravity, load transfer during maneuvers, steering kinematics, and the like). In order to accurately measure tire tread wear and make comparisons between various tire models, testing must be conducted in such a manner as to hold constant the influences from the environment, driver severity, pavement, and vehicle so as to not bias the tread wear results. Vehicle characteristics can have a significant effect on a tire's wear rate and cause an irregular wear propensity. As long as all tires in the test are evaluated on the same vehicle model, the bias introduced by the vehicle will be the same for all test tire models.
Some tires, such as original equipment manufacturer (“OEM”) tires, are developed specifically for a particular vehicle. In this case, tire testing should be done on the specific OEM vehicle, or, if tested on an indoor tire test machine, the vehicle should be precisely simulated. However, many tires are designed as a replacement to worn or damaged OEM tires; these tires are referred to as “trade tires.” Trade tires may not be developed specifically for one particular vehicle, but rather, for an entire market segment of vehicles comprising a large variety of tire sizes and respective load capacities. A variety of sizes and different tire load requirements will normally require testing on different vehicles, which may have different ballast conditions. When this is the case, the vehicle-to-vehicle bias and the test tires' wear performances are inseparable. For indoor tire testing, it is desirable to create a vehicle model that is “typical” of the vehicles in a certain segment (for example, front wheel drive sedans or pick-up trucks), and which is continuously scalable to different loads.
Contemporary practice for tire manufacturers, for example when testing trade tires for the National Highway Traffic Safety Administration's Uniform Tire Quality Grading (“UTQG”) standard for relative grading of tires for tread wear, is to test each tire on some number of specific vehicles. For example, testing may be performed on an actual vehicle driving the 640 km UTQG road course in Texas. Testing may also be performed on an indoor tire test machine that is configured to apply to a test tire certain forces at certain inclination angles to simulate the forces and inclination angles the tire would see on the actual UTQG road course. This latter method typically involves less time and money than the former method. For example, an outdoor UTQG test may take more than two weeks to plan, prepare, and execute. By contrast, an indoor UTQG wear test may take less than one week to plan, prepare, and execute. Moreover, an outdoor UTQG test may require a team of people dedicated to the test, whereas an indoor UTQG wear test may be run by one person on an automated tire wear test machine. Regardless of which testing method is chosen, the contemporary practice has been to test a tire on a specific vehicle to obtain that tire's tread wear rating on that vehicle. The goal for this method is to develop tire wear tests that produce the most accurate results possible for a particular vehicle. Tire manufacturers then use this wear rating on their tires to be used on many different vehicles within a market segment. However, due to vehicle bias, there can be significant variation between a tire's tread wear rating and the actual tread life it will experience when mounted to a vehicle on which it was not tested. Such discrepancies may lead to consumer frustration and dissatisfaction, either in the tire or in the tire manufacturer, because the actual tire wear mileage observed may be far less than the tire wear mileage indicated by the tire's UTQG wear rating.
What is needed is a low cost method for testing tires that allows for a more accurate tire wear rating across a wider variety of vehicles, resulting in higher consumer confidence and satisfaction. Tire testing systems and methods are needed to permit indoor simulation testing of tires of a wide range of sizes on a scalable vehicle model (“SVM”), which would alleviate the need for testing tires on multiple vehicles and which would permit the measurement of tire wear and performance without vehicle-to-vehicle bias.